This is a relatively easy swap. The engine will bolt right in. The Vortec 350 is based on the Gen 1 350 4 bolt main block. The motor mounts and transmission should match right up.
Because of its age, use an aftermarket intake manifold for the Vortec and use a carburetor. The will eliminate the problems of trying to make the late model fuel injection work.
Use the HEI distributor from the original Vette motor. If this is not available there are lots of good aftermarket HEI distributors out there.
You may need to get creative making the accessories work. I would use the serpentine belt system and accessories from the Vortec. However you may need to alter your wiring harness to accept the newer alternator.
I think that the exhaust manifolds use the same bolt pattern so you should be able to connect the exhaust from the Vette with little problems. However the first generation catalytic converters were very restrictive and really choked the 76 Vette engine. If possible, lose the catalytic converters. If this is not possible add some new low restriction catalytic converters.
Performance will be better with a Vortec. Value may not increase all that much. This is because to a collector the engine number must match the car. Your Vette will no longer have the matching number engine. However the 76 Vette was one of the worst performing models made so it is not very desirable to collectors. But it is still a Vette and any Vette is cool.
